import XLSX from 'xlsx'
export default {
  methods: {
    exportExec(workbook, title) {
      var wopts = {
        bookType: 'xlsx', // 要生成的文件类型
        bookSST: false, // 是否生成Shared String Table，官方解释是，如果开启生成速度会下降，但在低版本IOS设备上有更好的兼容性
        type: 'binary'
      }
      var wbout = XLSX.write(workbook, wopts)
      var blob = new Blob([s2ab(wbout)], { type: 'application/octet-stream' }) // 字符串转ArrayBuffer
      function s2ab(s) {
        var buf = new ArrayBuffer(s.length)
        var view = new Uint8Array(buf)
        for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xff
        return buf
      }
      this.openDownloadDialog(blob, title)
    },
    openDownloadDialog(url, saveName) {
      if (typeof url === 'object' && url instanceof Blob) {
        url = URL.createObjectURL(url) // 创建blob地址
      }
      var aLink = document.createElement('a')
      aLink.href = url
      aLink.download = saveName || '' // HTML5新增的属性，指定保存文件名，可以不要后缀，注意，file:///模式下不会生效
      var event
      if (window.MouseEvent) event = new MouseEvent('click')
      else {
        event = document.createEvent('MouseEvents')
        event.initMouseEvent(
          'click',
          true,
          false,
          window,
          0,
          0,
          0,
          0,
          0,
          false,
          false,
          false,
          false,
          0,
          null
        )
      }
      aLink.dispatchEvent(event)
    }
  }
}
